Patent GB-1328436-A (GB)
Title: Vehicle driving systems by the storage of sustained kinetic energy
IPC: F03G3/00
Filed: 1971-04-19
Abstract: 1328436 Momentum power-storing apparatus SOC ANON DE VEHICULES INDUSTRIELS ET D'EQUIPEMENTS MECANIQUES 19 April 1971 [16 March 1970] 24115/71 Heading F2X [Also in Division B7] A device for driving a vehicle, in particular a passenger transport bus, incorporating a periodically rechargeable kinetic accumulator consisting of the rotor of a high-speed electric generator supplying in a variable and reversible manner electric motors for driving the wheels of the vehicle, the motors being adapted on downhill road sections and during brake applications to operate as generators and recharge the rotor/ kinetic accumulator of the generator which in this case operates as a motor. As shown, a thermal engine 1, e.g. a diesel engine, drives through a freewheel 2 and a step-up gearing 3 an alternator 4 delivering 3-phase electric current via lines 5 and 6 to wheel-driving motors (not shown). The accelerator lever 22 of the engine 1 can be set in only two stable positions, determined by a full-speed stop 23 and an idling stop 24. The lever 22 is responsive to the piston-rod 25 of a pneumatic actuator 26, the piston 27 of which is adapted to be moved against a return spring 28 when compressed air is supplied to a pipe-line 29 from a 2-way solenoid valve 30. The valve 30 is responsive to a control box 40 from an electric tachometer 41 connected to one phase of the 3-phase conductor 5. A potentiometer 38 actuated by the accelerator pedal 37 is connected to a power reference box 44 connected in turn to the junction between boxes 40 and 41. Beyond a predetermined position of pedal 37 a contact 45 is closed and this permits the passage of current through a conductor 46 to box 40 for locking the valve 30 in the full-speed position. Beyond a predetermined position of brake pedal 34 a contact 47 is closed to permit the passage through a conductor 48 of energizing current to a relay 49 whereby the main 3-phase current is diverted through line 50 to a set of braking resistors 51 (only one shown). The torque transmitted to the vehicle wheels is controlled directly from the accelerator by actuating the potentiometer 38. To avoid any overload in the generator when its speed is not sufficient to permit the transmission of the maximum possible power output to the wheels, the potentiometer 38 is energized from the power reference box 44 of which the output voltage is limited as a function of the alternator speed. During the brake applications the resistors 51 are energized only when the alternator has attained its maximum speed, this energization taking place through relay 49 and contact 47 closed by the brake pedal 34 with the control voltage of solenoid valve 30. The engine 1 drives the alternator 4 up to the maximum speed contemplated; if the power demand is moderate and the alternator speed tends to increase beyond the maximum contemplated, the engine 1 is cut off automatically by a regulator and restored to its idling speed; the rotor of alternator 4 assumes the demanded power output so that its speed decreases; below a predetermined minimum speed the engine 1 is re-started and its speed rises almost instantaneously to the value of the alternator speed so as to drive the alternator 4 through the freewheel 2. When it is desired to dissipate power, during motion downhill and during brake applications, the wheel-driving motors are operated reversely to deliver electric current which, by causing the alternator 4 to operate as a motor, increases the alternator speed and therefore recharges the kinetic accumulator up to the maximum speed value beyond which electric current is delivered to the braking resistors 51. In the case of zero power demand, the losses of speed of the alternator rotor as a consequence of bearing friction are compensated at least partially by a continuous driving action derived from a pump 13 for pressurizing the lubricating and cooling oil, which pump is driven by an auxiliary electric motor 14.